code: def test_invalid_layer(self):
      m = maps.Map()
      with self.assertRaises(traitlets.TraitError):
          m.layers = [52]
  
file_path: gmaps/gmaps/tests/test_maps.py
imports: import unittest
  import traitlets
  from ..None import maps, heatmap_layer
label_desc: Use image node_id 4 for calling the Map obj's underlying member method code with example usage: obj.test_invalid_layer() without return types